Corbett is running on a record that includes support for the energy industry, particularly shale gas drilling, and creating more than 140,000 private-sector jobs.
His campaign website also says Pennsylvania spends more on education than at any other time in its history.
Valentino DiGiorgio, chair of Chester County's Republican Party, said Democrats have successfully spun the education funding issue to claim Corbett cut school spending statewide. DiGiorgio said Corbett actually raised it - without hiking taxes - when federal stimulus dollars that the Rendell administration used for education ran out.
No Republicans have announced plans to run against Corbett, but eight Democrats are interested. His campaign has attacked front-runner U.S. Rep. Allyson Y. Schwartz with claims that she would raise taxes.
Released Thursday, a Franklin and Marshall College poll of 628 registered voters found that 61 percent think the state is on the wrong track. Twenty percent said Corbett had "performed sufficiently well to deserve reelection."
Corbett's highest performance rating so far was in 2011, when about 39 percent said he did a good or excellent job. That peak has failed to match the lowest poll numbers of Republican Tom Ridge's tenure and barely eclipsed Democrat Ed Rendell's nadir.
"Pennsylvanians are continuing to reject Tom Corbett's failed record," said Marc Eisenstein, a spokesman for the state's Democratic Party. "It is no surprise that Pennsylvania is ready for a change."